You need a system which dynamically checks the blockchain pending withdrawals and adjusts the withdrawal fee instead of having a fixed 20K, 40K and 60K fee amount. This whole issue is affecting the Bitsler reputation. Many users look like not happy with the recent delays from Bitsler withdrawals. You need to find a solution for this issue or you need to allow users to select the withdrawal fee.
AFAIK, most dice gambling sites have the same withdrawal system as bitsler. It's been run for a long long time and it has only minor issues. If for example bitsler changed their withdrawal system by allowing users to pick their own fees, manually put the transaction fees, do you think there will be no more complains regarding withdrawal issues?
The current system is already running as expected then it does not need to be touched let alone changed.